High volume hydraulic recoil pump

ABSTRACT

A subsurface pump which delivers a high volume of fluid from a well, and also attains &#39;&#39;&#39;&#39;hydraulic recoil.&#39;&#39;&#39;&#39; The latter term refers to the feature that the column of fluid in the well above the pump acts against the moving parts of the pump to assist the sucker rods in driving the parts downwardly during a downstroke. Previously known pumps may achieve either high volume or hydraulic recoil, but usually not both. Hydraulic recoil is needed in pumps which handle heavy viscous oil to relieve the sucker rods of compressive stresses tending to buckle them.

United States Patent Heard [45] Nov. 1l, 1975 [541 HIGH VOLUME HYDRAULIC RECOIL 2,191.38@ 2/1940 Hall 417/546 PUMP 2.296.821 9/1942 Puis 417/260 2,684,639 7/1954 Sutton 417/26() [75l Inventor: Allen C. Heard, Monahans, TeX. 3,136.265 6/1964 Chenaun 417/447 4 [73] Assignee: United States Steel Corporation, gg; i; 2x23? Pittsburgh Pa [22] Filed: Sept. 10, 1973 Pri/mir)` Examiner-William L. Freeh [2l] Appl- NO': 395,789 Attorney, Agent, 0r Firm-Walter P. Wood [57] ABSTRACT A Subsurface pump which delivers a Volume of [58] Ft'ld F04? To fluid from a well, and also attains hydraulic recoil. 1 le o earc I7/ 6 2 5 7 The latter term refers to the feature that the column 417/554 261 260 92/865 of fluid in the well above the pump acts against the moving parts of the pump to assist the sucker rods in [56] References cned driving the parts downwardly during a downstroke.

UNITED STATES PATENTS Previously known pumps may achieve either high vol- 35,577 6/1862 Andrews 417/546 ume or hydraulic recoiL but usually not both. Hydrau- 208285 9/1878 Beemn eral... 417/546 lic recoil is needed in pumps which handle heavy vis- 767,454 8/1904 Taylor 417/546 C0115 Oil to relieve the sucker rods 0f compressive 2.067.774 l/l937 Matthews et al. 417/260 Stresses tending to buckle them' 2,138,002 11/1938 Hall 1 417/260 2,166,612 7/1939 Scott 417/547 4 Claims, 2 Drawing Figures n /0` [I E/ets 3 F`30 -3/ 3 I z ,5 11 1 l uPsrRa/(E s l i /7 t r j f /9-- i; N l2` la `T US, Patent Nov. 11, 1975 UPS TRO/(E HIGH VOLUME HYDRAULIC RECOIL PUMP This invention relates to an improved subsurface pump for use in oil wells or the like.

The pump is an improvement over the pumps shown and claimed in the commonly owned Anderson and Rohrig U.S. Pat. Nos. 3,140,667 and 3,479,958. The former shows a type of pump which has become known in the trade as a "hydraulic recoil"pump. lDuring a downstroke of the pump parts, the weight of the column of fluid in the tubing above the pump acts against the moving parts and assists the sucker rods in driving these parts downwardly. Hence the sucker rods are relieved of compressive stresses which tend to buckle them. A hydraulic recoil pump is advantageous for pumping heavy viscous oils which resist downward movement of the parts, but previously known hydraulic recoil pumps do not deliver a high volume of fluid from a well. During an upstroke, the pump delivers fluid to the surface from only an annular chamber, of relatively small cross-sectional area, and during a downstroke delivers no fluid. The latter patentshows a high-volume pump which delivers fluid on both upstroke and downstroke, but which does not have the advantage of hydraulic recoil during adownstroke. The sucker rods must sustain the full compressive load required to drive the parts downwardly.

An object of the present invention is to provide an improved subsurface pump which affords the advantages of both hydraulic recoil and high volume.

A further object is to provide an improved subsurface pump which affords the advantage of hydraulic recoil brought about by a pressure differential on opposite sides of the moving parts, but which also achieves highvolume operation.

In the drawing:

FIG. l is a diagrammatic vertical sectional Vview of the lower portion of a well equipped with a pump constructed in accordance with my invention, showing the position of the parts during an upstroke; and l FIG. 2 is a similar view, but showing the position of the parts during a downstroke. i

The drawing shows the lower portion of a conventional well tubing l which includes a seating nipple 12 near its lower end. The pumpof my invention includes upper and lower stationary barrels 13 and 14 and upper and lower hollow plungers 15 and 16 movable up and down within the respective barrels. A tubular connecting plunger 17 of smaller diameter than plungers 15 and 16 joins the two plungers. A packoff 18 is situated between the two barrels 13 and 14 and closely receives the connecting plunger 17. The upper barrel has an external shoulder 19 located a short distance above its lower end, and it carries cup or ring-type sealing rings 20 immediately beneath said shoulder. The shoulder seats on the upper face of the seating nipple l2, while the sealing rings are received within nipple. Preferably the sealing rings themselves are constructed as shown in the aforementioned Anderson and Rohrig U.S. Pat. No. 3,479,958, but in contrast to the showing of the patent, the shoulder and sealing rings are located above the packoff 18.

A conventional string of sucker rods 21 is connected to the upper plunger 15 for raising and lowering the plungers. The lower barrel 14 carries a conventional 6 cated near the upper end of plunger l5 and valve 24.Io cated near the lower end of plunger 16, either valvc can be located elsewhere in its respective plunger.

The upper end of barrel 13 has a port 25 which furnishes communication between a chamber 26 within the barrel above plunger l5 and the interior of tubing l0. The lower end of barrel 13 has a port 27 which furnishes communication between an annular chamber 28 within the barrel beneath plunger l5 and an annular passage 29. This passage lies between the exterior of the barrels and the interior of tubing 10 and communicates with the producing formation of the well. Port 25 is located above the sealing rings 20 and port 27 below. The upper end of plunger 15 has a port 30 which furnishes communication between a chamber 3l within the plunger above valve 23 and chamber 26. The upper end of plunger 16 has a port 32 which furnishes communication between a chamber 33 within the plunger and an annular chamber 34 within barrel 14. Chamber 33 extends through the connecting plunger 17 into the upper plunger 15. The interior of the lower barrel 14 beneath plunger 16 constitutes a chamber 35.

In operation, during an upstroke shown in FIG. l, the standing valve 22 and the upper traveling valve 23 both open and the lower traveling valve 24 closes. Well fluid is drawn into chamber 35 in the lower barrel 14. Fluid previously admitted to chamber 33 within the plungers is lifted through chamber 31, port 30, chamber 26, and port 25 into the interior of tubing l0 and thence delivered to the surface. Fluid previously admitted to the annular chamber 34 in the upper portion of barrel 14 flows through port 32 into chamber 33. Well fluid also is drawn through passage 29 and port 27 into chamber 28 within the upper barrel 13.

During a downstroke shown in FIG. 2, the standing valve 22 closes and the lower traveling valve 24 opens. The upper traveling valve 23 is essentially closed, but may open through a portion of the downstroke. Fluid previously admitted to chamber 35 flows through valve 24 into chamber 33. Most of this fluid flows through port 32 into the annular chamber 34, but a portion may flow through valve 23, chamber 3l, port 30, chamber 26, and port 25 into the tubing 10 and thence is delivered to the surface. Fluid previously admitted to chamber 28 flows through port 27 and passage 29 back into the well.

As long as valve 23 remains closed during a downstroke, the column of fluid in tubing 10 acts fully against the upper plunger l5 and drives the plungers downwardly, as in the hydraulic recoil pump shown in the aforementioned Anderson and Rohrig U.S. Pat. No. 3,140,667. During the full downstroke the lower end of the upper plunger l5 is under negative pressure or suction, since chamber 28 is in communication with the well through port 27 and passage 29. Thus even though valve 23 opens, the pressure differential on the upper plunger produces a net force in the downward direction and the hydraulic recoil effect is maintained. At the same time the pump delivers a high volume of fluid. During an upstroke the full cross sectional area of the plungers, except for the area occupied by the sucker rods 2l, is effective to deliver fluid. During a downstroke additional fluid is delivered whenever valve 23 opens.

I claim:

l. In a subsurface pump which includes:

upper and lower barrels;

upper and lower plungers movable up and down in the respective barrels and providing variable volume chambers both above and below each plunger in each barrel, the chamber below said upper plunger being annular;

connecting means rigidly joining said plungers;

said upper plunger having an upwardly facing area and a downwardly facing area, both of which areas are subject to fluid pressure, said upwardly facing area constituting the major portion of the crosssectional area of the plunger;

said lower plunger having an upwardly facing area subject to fluid pressure;

means between said barrels closely receiving said connecting means;

a standing valve in said lower barrel, which standing valve opens during an upstroke of said plungers and closes during a downstroke thereof; and

upper and lower traveling valves in said upper and lower plungers respectively, both of which traveling valves open during an upstroke of said plunger, which lower traveling valve closes during a downstroke, and which upper traveling vlave closes during most of a downstroke; y the improvement comprising:

means acting during a downstroke of said plungers to subject the upwardly and downwardly facing areas of said upper plunger respectively to relatively high pressure of a column of fluid above the pump and to relatively low pressure of well fluid surrounding the pump to assure a net downward force acting on said upper plunger to provide hydraulic recoil; means acting during an upstroke of said plungers to deliver fluid from the entire upwardly facing area of said upper plunger to provide a high volume of l fluid delivery;

said upper traveling valve opening during a portion of a downstroke to deliver fluid;

whereby both hydraulic recoil and high volume are obtained in one pump.

2. A pump as defined in claim l in which said means acting during a downstroke includes the annular chamber beneath said upper plunger, said annular chamber being subject to suction pressure during a downstroke.

3. A pump as defined in claim 2 in which said upper barrel has a port furnishing communication between said annular chamber and the well, and said pump includes in addition seating means on the exterior of said upper barrel above said port.

4. A subsurface pump comprising: upper and lower barrels; upper and lower hollow plungers movable up and down in the respective barrels and providing variable volume chambers both above and below each plunger in each barrel; a tubular connecting plunger rigidly joining said upper and lower plungers; said upper plunger having an upwardly facing area and a downwardly facing area, both of which areas are subject to fluid pressure, said upwardly facing area constituting the major portion of the crosssectional area of the plunger; said lower plunger having an upwardly facing area subject to fluid pressure; packoff means between said barrels closely receiving said connecting plunger;

a standing valve in said lower barrel; upper and lower traveling valves in the respective upper and lower plungers; and

seating means on the exterior of said upper barrel above said packoff means;

said plungers having ports above the respective traveling valves;

said upper barrel having a port below said seating means, the variable volume chamber in said upper barrel below said upper plunger communicating with the well through said lastnamed port, whereby fluid is drawn into this chamber through this port during an upstroke and discharged therethrough into the well during a downstroke;

the upwardly and downwardly facing areas of said upper plunger being subject during a downstroke of said plungers respectively to relatively high pressure of a column of fluid above the pump and to relatively low pressure of well fluid surrounding the pump to assure a net downward force acting on the upper plunger to provide hydraulic recoil;

the entire upwardly facing area of said upper plunger being effective during an upstroke to deliver fluid to provide a high volume of fluid delivery.

* 1k Ik 2k 

1. In a subsurface pump which includes: upper and lower barrels; upper and lower plungers movable up and down in the respective barrels and providing variable volume chambers both above and below each plunger in each barrel, the chamber below said upper plunger being annular; connecting means rigidly joining said plungers; said upper plunger having an upwardly facing area and a downwardly facing area, both of which areas are subject to fluid pressure, said upwardly facing area constituting the major portion of the cross-sectional area of the plunger; said lower plunger having an upwardly facing area subject to fluid pressure; means between said barrels closely receiving said connecting means; a standing valve in said lower barrel, which standing valve opens during an upstroke of said plungers and closes during a downstroke thereof; and upper and lower traveling valves in said upper and lower plungers respectively, both of which traveling valves open during an upstroke of said plunger, which lower traveling valve closes during a downstroke, and which upper traveling vlave closes during most of a downstroke; the improvement comprising: means acting during a downstroke of said plungers to subject the upwardly and downwardly facing areas of said upper plunger respectively to relatively high pressure of a column of fluid above the pump and to relatively low pressure of well fluid surrounding the pump to assure a net downward force acting on said upper plunger to provide hydraulic recoil; means acting during an upstroke of said plungers to deliver fluid from the entire upwardly facing area of said upper plunger to provide a high volume of fluid delivery; said upper traveling valve opening during a portion of a downstroke to deliver fluid; whereby both hydraulic recoil and high volume are obtained in one pump.
 2. A pump as defined in claim 1 in which said means acting during a downstroke includes the annular chamber beneath said upper plunger, said annular chamber being subject to suction pressure during a downstroke.
 3. A pump as defined in claim 2 in which said upper barrel has a port furnishing communication between said annular chamber and the well, and said pump includes in addition seating means on the exterior of said upper barrel above said port.
 4. A subsurface pump comprising: upper and lower barrels; upper and lower hollow plungers movable up and down in the respective barrels and providing variable volume chambers both above and below each plunger in each barrel; a tubular connecting plunger rigidly joining said upper and lower plungers; said upper plunger having an upwardly facing area and a downwardly facing area, both of which areas are subject to fluid pressure, said upwardly facing area constituting the major portion of the cross-sectional area of the plunger; said lower plunger having an upwardly facing area subject to fluid pressure; packoff means between said barrels closely receiving said connecting plunger; a standing valve in said lower barrel; upper and lower traveling valves in the respective upper and lower plungers; and seating means on the exterior of said upper barrel above said packoff means; said plungers having ports above the respective traveling valves; said upper barrel having a port below said seating means, the variable volume chamber in said upper barrel below said upper plunger communicating with the well through said lastnamed port, whereby fluid is drawn into this chamber through this port during an upstroke and discharged therethrough into the well during a downstroke; the upwardly and downwardly facing areas of said upper plunger being subject during a downstroke of said plungers respectively to relatively high pressure of a column of fluid above the pump and to relatively low pressure of well fluid surRounding the pump to assure a net downward force acting on the upper plunger to provide hydraulic recoil; the entire upwardly facing area of said upper plunger being effective during an upstroke to deliver fluid to provide a high volume of fluid delivery. 